The fuze has a cylindrical body, approximately 1.5 inches in length and 0.87 inch in dia-meter, from the head of which the hemispherical of the striker, with its supporting shear-ing pin, protrudes. At the base end, the main detonator for the mine is attached by means of a screwed adapter sleeve. The fuze is painted the normal dark olive green.

The body is of steel and is in the form of an inverted cup with a hole at the head through which the outer end of the striker protrudes. The base is closed by the cap hol-der, which is secured by the body being turned inwards under its flange.

The steel striker has a central striking projection at its inner end where is flanged to en-gage one end of the steel spiral spring. A slot, for the escape of air during the function-ing of the striker, is cut through the flange. The spiral spring is held in compression bet-ween the flange and the upper end of the body by a mild steel shearing pin. The pin is fitted in a lateral channel in the striker from which the ends protrude and bear on the re-cessed top of the body. The diameter of the pin is 0.079 inch and the V.D. Hardness fi-gure is 232.

The cap holder contains a percussion cap and anvil assembly in a central channel and is screwthreaded externally to receive the adapter for the attachmend of the main detona-tor.

The cap and anvil assembly is contained in a copper sheath. The cap is of copper and contains a 0.77 grain filling consisting of 40.8 per cent of lead styphnate, 40.7 per cent of barium nitrate, 2.9 per cent of antimony sulphide and 15.6 per cent of calcium silicide. The filling is partly covered by a paper washer varnished on both sides, and is pressed to form a central cavity to fit over the anvil. The cavity is also varnished. The anvil con-sists of a brass strip shaped to fit into the mouth of the cap with clearance for the pas-sage of the flash at each side of the strip. Projections at the base ends of the strip are bent to form a ring, under which the wall of the copper sheath its turned inwards.

The screwed adapter sleeve is of very light construction and has an internal flange at the base to engage a corresponding flange on the main detonator.

The light metal body of the main detonator is cylindrical with an external flange at its open upper end. The filling comprises 12 grains of P.E.T.N. with an initiator topping con-sisting of lead azide 58.9 per cent, lead styphnate 39.2 per cent and graphite 1.9 per cent. The composition is contained in an inverted light metal capsule which is pressed down into the mouth of the body. A central flash hole in the capsule is closed at the un-derside by a disc of black gauze material.

The load required to actuate the fuze in the mine varies between 570 and 580 lb. if app-lied to the cover plate above the fuze. With the load applied near the outer edge of the main cover plate the lever effect reduces the required load which may be as low as one half of the amount.

With the fuze removed from the mine, so that the resistance of the spring under the cover plate is excluded and only the shearing pin has to be severed, the load required is 495 lb.